Electrode wire

ABSTRACT

The invention relates to the field of welding. Disclosure is made of a wire comprising a metal body (1) having a longitudinal cavity (3) filled with a charge (2) comprising at least one constituent from the group consisting of alloying and slag-forming constituents. 
     On the surface of the cavity (3) and the wire there is disposed a coat (4, 7) made up of at least two layers (5, 6 and 8, 9). Each of said layers (5, 6 and 8, 9) incorporates one constituent selected from the group consisting of alloying and slag-forming constituents. From 10 to 99 percent of the mass of the constituents in the layers (5, 6) of the coat (4) and in the layers (8, 9) of the coat (7) is disposed on the surface of the cavity (3), and the total area of the layers (5, 6) of the coat (4) and the layers (8, 9) of the coat (7) in cross section of the wire, incorporating the identical constituents, amounts to from 0.001 to 0.1 part of the area of the metal body (1).

TECHNICAL FIELD

The present invention relates to the field of welding, and in particularto an electrode wire comprising a metal body and a charge.

BACKGROUND OF THE INVENTION

Nowadays the consumable-electrode arc welding in shielding (oxidizingand inert) gases is the most widely used method of welding in theindustry. In construction and on erection sites there is used unshieldedconsumable-electrode arc welding. Used as consumable electrodes areelectrode wires of solid section and electrode wires having innercavities filled with a powdered charge. A solid-section wire isessentially a homogeneous monolithic long metal rod. The electrode wirehaving inner cavities is a composite material comprising a thin-walledmetal sheath of tubular or more complex section, and a charge. Thecharge enclosed in the inner cavity defined by the electrode wire sheathis a mechanical mixture of metal powders (iron powder, ferroalloys,alloying powders), slag-forming and stabilizing constituents. The ratioof cross-section area of the charge-filled cavity in the electrode wirehaving inner cavities to cross-section area of the whole wire usuallyequals from 0.5 to 0.8.

In welding with the use of solid-section wires both in shielding gases,especially oxidizing ones, and without additional shielding there occursan increased spattering of electrode metal, as well as an unsatisfactoryweld formation. To prevent formation of pores in the process of weldinglow-carbon and low-alloy steels, the electrode wires of solid sectionobligatorily comprise deoxidizers such as silicon, manganese, titanium,aluminium, having a closer affinity for oxygen than iron, as well as insome cases alloying constituents such as chromium, vanadium, molybdenum.The deoxidizers and alaloying elements present in the electrode wireworsen its ductility, make the process of manufacturing a small (0.6 to1.6 mm) diameter wire needed for welding more complicated and expensive.It should be noted that the better quality of weld metal is required,the greater amount of alloying and deoxidizing elements will becontained in the wire and the lower will become its ductility(deformability). However, the presence of any of presently knowncombinations of alloying and deoxidizing elements in the composition ofthe solid-section wire fails to prevent spattering of electrode metal,as well as to substantially improve formation of a weld surface whenwelding in the shielding gases and to provide the required performanceof the weld metal when using unshielded arc welding.

The electrode wires having inner cavities filled with the charge make itpossible to obtain quality welds featuring high performance both ingas-shielded and unshielded arc welding. Ability of the electrode wirehaving inner cavities to deform in the process of cold working changesbut slightly with a greater or smaller amount of alloying constituentspresent in the charge. However, in contrast to the solid-section wiresthe electrode wires having inner cavities are difficult-to-manufactureand need special feeding mechanisms having several pairs of feed rollsand applying inconsiderable unit pressure on the surface of wire made,as a rule, of cold-rolled low-carbon steel from 0.15 to 0.5 mm thick.Metal powder constituents in the composition of the charge of theelectrode wire, mixed with slag-forming constituents are susceptible tocorrosion, which limits the storage life of such wires; therefore thewelding process with use of the electrode wire having inner cavities isinsufficiently reliable for obtaining high-quality welds.

The charge of the electrode wire having inner cavities in spite of greatamount of metal constituents (iron powder and ferroalloys) presenttherein does not conduct electric current and therefore, in the processof welding with use of such a wire, melting of its core considerablylags behind melting of its metal sheath. As a result of insufficientheating voluminous portions of the charge pass into a welding poolwithout melting-down, which decreases the effectiveness of a slag shieldof droplets of molten metal in the process of their growth at theelectrode end face and transfer into the welding pool, i.e. some part ofthe slag does not participate in protection of the molten metal from theatmospheric air. Thus the self-shielded electrode wires having innercavities contain from 15 to 20 mass percent of shielding slag-formingmaterials in the charge which results in a lower welding efficiencythereof compared to solid-section wires.

Deformability in manufacture of the electrode wire having inner cavitiesis substantially lower than that of the solid-section wire as thethin-walled sheath whose strength is limited when being deformed shouldtake a load produced by both the resistance to deformation of materialof the sheath and resistance to deformation of the powdered change.Therefore, the process of manufacturing the electrode wires having innercavities of small diameter is more complicated than the process ofmanufacturing the solid-section wires.

An increase in the melting efficiency of the electrode wire withmaintaining good welding and fabrication characteristics of theelectrode wire having inner cavities may be achieved in case of using awire comprising a metal body incorporating alloying and deoxidizingconstituents and a powdered charge located in longitudinal ducts of themetal body.

Most similar prior art disclosing a subject matter closely associatedwith the present invention is GB, A, No. 1,481,140 describing anelectrode with comprising an alloyed metal body having at least onelongitudinal cavity filled with a charge comprising at least oneconstituent selected from the group consisting of slag-forming andalloying constituents.

As distinct from the solid-section wire such a wire features a minimumspatter and quality weld formation. Moreover, this wire has a sufficientstiffness since it is manufactured not from a strip but from a shapedblank and does not require the use of special multiple-roll feedmechanisms. However, it is impossible to manufacture said wire with adiameter less than 1.6 mm because of a low ductility of the metal body.But is known that to obtain welds ensuring serviceability of structuresmade of steels comprising alloying constituents is possible only withuse of the wire with a diameter of 1.6 mm and less for welding. The lowductility of the metal body depends on alloying constituents presenttherein. The greater the mass of the alloying constituents, the lower isductility of the metal body. The requirements for a constant chemicalcomposition throughout the metal body volume do not allow hot workingand heat treatment to be performed after cold working of the metal body.The high temperature causes the chemical composition of near-the surfacelayers of the metal body to change due to interaction with the ambientatmosphere. In such a case the 1.6-mm diameter wire will have a metalbody with chemical composition thereof upset in more than half of itsvolume, which will adversely affect the quality of the weld. Thus, thewire should be manufactured by cold working. However, it is impossibleto obtain the wire of so intricate configuration of cross sectionwithout additional heat treatment due to the low ductility of the metalbody. Moreover, even if the main part of the alloying constituentsnecessary for welding is introduced in the charge of the electrode wiretheir losses amount to from 20 to 90 percent depending on the weldingconditions and affinity of the alloying constituent for oxygen.Therefore, introduction of alloying constituents in the composition ofthe wire metal body impairs its deformability, and the presence thereofin the charge composition brings about considerable burn-out lossesduring welding.

SUMMARY OF THE INVENTION

The principle object of the invention is to provide such an electrodewire featuring such a structure, chemical and quantitative compositionthat would ensure high ductility of the metal body when subjected tocold working thus making it possible to manufacture a wire having goodwelding and fabrication characteristics, that is, minimum losses ofalloying elements in the process of melting thereof, a high efficiencyof the welding process and a highly effective utilization of heat ofmelting thereof.

The problem stated above is solved by that in an electrode wirecomprising an alloyed metal body having at least one longitudinal cavityfilled with a charge incorporating at least one constituent from thegroup consisting of slag-forming and alloying constituents, according tothe invention, disposed on surfaces of the cavities and the wire is acoat made up of at least two layers each comprising a constituentselected from the group consisting of alloying and slag-formingconstituents, from 10 to 99 percent of the constituents of the coatlayers being disposed on the surfaces of the cavities and the total areaof the coat layers in the wire cross section, comprising the identicalconstituents, amounts to from 0.001 to 0.1 part of the metal body area.

The main advantage of the wire of such a design is that disposition ofalloying and slag-forming constituents on the surface of the cavitiesand the wire imparts new properties to the material of the metal bodyduring cold working thereof, namely a high ductility of the metal bodymaterial, which manifests itself in an increased ability of the metalbody to deform without breaking.

The advantages of such a wire over the prior art wires of similar typereside in a reduced consumption of alloying and slag-formingconstituents for welding. Concentration of the major part of thealloying constituents not within the volume of the metal body but on thesurfaces of the wire and cavities improves deformability of the wire. Adecrease in quantity of the alloying and slag-forming constituents inthe slag and application thereof to the surfaces of the cavities and thewire minimizes losses of the alloying elements in the process of wiremelting as in this case the surface of their contact with the slag andgases in the process of wire heating prior to melting is less by one ortwo orders of magnitude. The quantity of constituents located in thecavities of the wire of such a design is brought to a minimum, whichprovides for a more effective utilization of heat for heating andmelting the wire. Moreover, the slag-forming constituents not conductingcurrent under usual conditions become conductors, if applied to thesurface in the form of a thin film, i.e. with a slag-forming constituentlayer on the surfaces of the wire and cavity thinner than a preset value(individual for each constituent) it is melted like the metal body withthe aid of heat released within the volume of the metal body due toelectrical resistance and not due to heat transfer from the metal body,which increases the welding process efficiency as well.

Disposition of less than 10 percent of the mass of constituents of thecoat on the surface of the cavities substantially affects the weldchemical composition since in the process of welding the coatconstituents are sublimated and oxidized to a considerable extent due tothe interaction with the ambient air. Application of more than 99percent of the mass of constituents of the coat to the surface of thecavities is associated with considerable difficulties in preventing theinteraction between the wire surface and a coat application source.

With the total area of one constituent being less than 0.001 part of thearea of the metal body its effect is inefficient as the expenditures forapplication of the coat become higher than the effect obtained from theimproved properties of the weld and increased productivity. With thetotal area of one and the same constituent exceeding 0.1 part of thearea of the metal body the efficiency of effect of the constituent alsodecreases as in this case the favourable effect of the coat on theefficiency of wire melting and productivity of melting is almostinappreciable but the expenditures for application of the coatdrastically rise.

Preferably the alloying constituents are selected from the groupconsisting of Mg, Al, Si, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Y, Zr, Nb, Mo,Cd, Ba, La, Ta, W, Ce.

Presence of these constituents on the surfaces of the cavities and thewire is stipulated by their ability to improve ductility of the metalbody and their alloying effect on the composition of the weld metal.

It is also preferable to select the slag-forming constituents from thegroup consisting of carbides, fluorides, chlorides and oxides of Mg, Al,Si, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Cd, Ba, La, Ta, W, Ce.

The advantages of such a wire compared with the prior art wires consistin an increased ultimate deformability thereof due to the improvedductility of the metal body. The improved ductility with high weldingand fabrication properties of the wire maintained is achieved due tolocation of the slag-forming constituents directly on the surfaces ofthe wire and cavities. It makes possible to obtain the wire having thediameter smaller than the diameter of the prior art wire. Besides,location of the slag-forming constituents on the surfaces of the wireand cavities makes it possible to reduce dimensions of the cavities and,hence, to increase the relative volume of the metal body in the wire andto carry out the welding process very efficiently. Moreover, a reliableprotection of molten metal with a slag envelope (formed during meltingof the slag) in the process of welding and an adequate detachability ofthe slag envelope from the surface of the weld are provided. Theeffective protection of the molten metal depends on the proposedlocation of the slag-forming constituents on the surfaces of thecavities and the wire.

It is preferable that the ductility of the constituent of the layeradjacent to the metal body and of the layer most distant therefrom ishigher than the ductility of the metal body.

Higher ductility of these layers compared with the ductility of themetal body makes it possible to improve still more the deformability ofthe material of the metal body. An increase in the ductility of themetal body is caused by the action produced thereon by the coat. Thenecessity of applying more ductile layers compared to the ductility ofthe metal body directly on the metal body depends on the mechanism ofplastic deformation which causes an increase in the ductility of themetal body. Higher ductility of the metal body in turn makes it possibleto obtain a small-diameter (less than 1.6 mm) wire and to increase thecapacity of the equipment.

The coat layers formed of constituents whose ductility is lower than theductility of the metal body may be arranged between the layers havingthe ductility higher than the ductility of the metal body.

In such a case in the process of drawing the wire its ultimatedeformability is increased as less ductile constituents are enclosed inductile covers and therefore can deform without affecting the generalability of the metal body to deform. An increase in the ultimatedeformability of the wire results in a higher efficiency of themanufacturing process and makes it possible to obtain a small diameterwire without additional heat treatment, which favourably affects thequality of the weld.

A coat whose layers comprise alloying and slag-forming constituentsconducting electrical current may be applied to the wire surface.

This improves supply of current to the metal body and increases theefficiency of wire melting in the process of welding.

Disposed on the wire surface may be a coat comprising at least threelayers of which the layer most distant from the metal body and the layeradjacent to it are made from alloying and slag-forming constituentsconducting electrical current, whereas the layer positioned therebetweenis made up of sections comprising alloying and slag-forming constituentsconducting electrical current and sections alternated therewith alongthe wire and comprising alloying and slag-forming constituents featuringa current-insulating property.

In this case it becomes possible to apply to the wire surface theconstituents having insulating properties but producing a favourableeffect on the welding process. The current-conducting sections make itpossible not to reduce the efficiency of welding and to provide uniformsupply of current to the metal body.

It is preferable to dispose on the wire surface a coat comprising atleast three layers of which the layer most distant from the metal bodyand the layer adjacent to it are made from alloying constituents,whereas the layer positioned therebetween is made from slag-formingconstituents.

This makes it possible to increase the ultimate deformability of thewire, to obtain small diameters of the wire and to ensure high qualityof the weld.

A coat may be disposed on the surfaces of the wire and cavities, inwhich the hardness of constituents of the layer adjacent to the metalbody and constituents of the layer most distant therefrom is lower thanthe hardness of the metal body.

This also makes it possible to increase the ultimate deformability ofthe wire as well as the efficiency of process of manufacturing thereof,and to obtain the wire of smaller diameters and the welds of betterquality.

Preferably, coat layers comprising constituents whose hardness is higherthan the hardness of the metal body to interpose between the layersincorporating constituents whose hardness is lower than the hardness ofthe metal body.

In this case in the process of plastic working of the wire it becomeseasier to deform the layers comprising constituents which are harderthan the metal body due to additional stresses arising in these layers.This in turn makes it possible to increase the ultimate deformability ofthe wire, to increase the efficiency of the manufacturing process, toobtain the wire of small diameters and to improve its quality.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a general view in cross section of an embodiment of theinvention representing an electrode wire having an oval cavity and atwo-layer coat on the surfaces of the wire and the cavity;

FIG. 2 is a general view in cross section of another embodiment of theinvention representing an electrode wire having a cylindrical cavitywith a four-layer coat applied to its surface and a two-layer coatapplied to the surface of the wire;

FIG. 3 is a cross section view of still another embodiment of theinvention representing an electrode wire having a complex-shaped cavityand a three-layer coat on the surfaces of the wire and the cavity;

FIG. 4 is a cross section view of an embodiment of the inventionrepresenting an electrode wire having four cylindrical cavities and athree-layer coat on the surfaces of the wire and the cavities;

FIG. 5 is a cross section view of an embodiment of the inventionrepresenting an electrode wire having three cylindrical cavities and afive-layer coat on the surfaces of the wire and the cavities;

FIG. 6 is a partially perspective cut-away view of an embodiment of theinvention representing an electrode wire having two cylindrical cavitiesand a three-layer coat on the surfaces of the wire and the cavities, themiddle layer of the coat on the surface of the wire being made ofalternate current-conducting and insulating sections.

BEST MODE OF CARRYING OUT THE INVENTION

An electrode wire of the invention shown in cross section in FIGS. 1through 6, comprises an alloyed metal body provided with at least onelongitudinal cavity filled with a charge comprising slag-forming andalloying constituents. According to the invention on surfaces of thecavities and of the wire there is disposed a coat made up of at leasttwo layers each comprising a constituent selected from the groupconsisting of alloying and slag-forming constituents. From 10 to 99percent of the mass of the layers of the coat is disposed on thesurfaces of the cavities, and the total area of the coat layers in crosssection of the wire incorporating the identical constituents equals from0.001 to 0.1 part of the area of the metal body. The alloyingconstituents are selected from the group consisting of Mg, Al, Si, Ca,Ti, V, Cr, Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Cd, Ba, La, Ta, W, Ce, and theslag-forming constituents are selected from the group consisting ofcarbides, oxides, chlorides and fluorides of Mg, Al, Si, Ca, Ti, V, Cr,Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Cd, Ba, La, Ta, W, Ce. The ductility ofthe constituents of the layer adjacent to the metal body and theductility of the constituents of the layer most distant therefrom arehigher than the ductility of the metal body. The coat layersincorporating the constituents the ductility of which is lower than theductility of the metal body are interposed between the layersincorporating the constituents the ductility of which is higher than theductility of the metal body. Disposed on the surface of the wire is acoat whose layers comprise alloying and slag-forming constituentsconducting electrical current. Disposed on the surface of the wire is acoat comprising at least three layers of which the layer most distantfrom the metal body and the layer adjacent thereto are made fromalloying and slag-forming constituents conducting electrical current,and the layer interposed between said layers is made up of sectionscomprising the alloying and slag-forming constituents conductingelectrical current and of sections alternated therewith and comprisingalloying and slag-forming constituents posessing a current-insulatingproperty, i.e. not conducting electrical current. Disposed on the wiresurface is a coat made up of at least three layers of which the layermost distant from the metal body and the layer adjacent thereto are madeof alloying constituents, whereas the layer interposed therebetween ismade of slag-forming constituents.

The hardness of the constituents of the layer adjacent to the metal bodyand of the layer most distant therefrom is lower than the hardness ofthe metal body. The coat layers comprising the constituents whosehardness is higher than the hardness of the metal body are disposedbetween the layers comprising the constituents whose hardness is lowerthan the hardness of the metal body.

An electrode wire shown in FIG. 1 incorporates an alloyed metal body 1and a charge 2 comprising at least one constituent from the groupconsisting of alloying and slag-forming constituents and disposed in anoval cavity 3. In accordance with the invention on the surface of thecavity 3 there is disposed a coat 4 made up of two layers 5 and 6. Eachof the layers 5 and 6 comprises one constituent selected from the groupconsisting of alloying and slag-forming constituents, whereas on thesurface of the wire there is disposed a coat 7 made up of two layers 8and 9. Each of the layers 8 and 9 comprises one constituent selectedfrom the group consisting of alloying and slag-forming constituents.From 10 to 99 percent of the mass of the constituents in the layers 5and 6 of the coat 4 and in the layers 8 and 9 of the coat 7 is disposedon the surface of the cavity 3, and the total area of the layers 5 and 6of the coat 4 and the layers 8 and 9 of the coat 7 in cross section ofthe wire, incorporating the identical constituents equals from 0.001 to0.1 part of the area of the metal body 1.

An electrode wire shown in FIG. 2 comprises a metal body 10 and a charge11 comprising at least one constituent from the group consisting ofalloying and slag-forming constituents and disposed in one longitudinalcylindrical cavity 12. According to the invention disposed on thesurface of the cavity 12 is a coat 13 made up of four layers 14, 15, 16and 17 each of which comprises one constituent selected from the groupconsisting of alloying and slag-forming constituents. Provided on thesurface of the wire is a coat 18 made up of two layers 19 and 20 each ofwhich comprises one constituent selected from the group consisting ofalloying and slag-forming constituents. The alloying constituents arealso selected from the group consisting of Mg, Al, Si, Ca, Ti, V, Cr,Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Cd, Ba, La, Ta, W, Ce, and theslag-forming constituents are also selected from the group consisting ofoxides, carbides, chlorides and fluorides of Mg, Al, Si, Ca, Ti, V, Cr,Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Cd, Ba, La, Ta, W, Ce. From 10 to 99percent of the mass of the constituents in the layers 14, 15, 16 and 17of the coat 13 and in the layers 19 and 20 of the coat 18 is disposed onthe surface of the cavity 12, and the total area of the layers 14, 15,16 and 17 of the coat 13 and the layers 19 and 20 of the coat 18 incross section of the wire, incorporating the identical constituents,equals from 0.001 to 0.1 part of the area of the metal body 10.

An electrode wire illustrated in FIG. 3 comprises an alloyed metal body21 and a charge 22 comprising at least one constituent from the groupconsisting of alloying and slag-forming constituents and disposed in acomplex-shaped cavity 23. According to the invention the surface of thecavity 23 has a coat 24 made up of three layers 25, 26 and 27 each ofwhich comprises one constituent selected from the group consisting ofalloying and slag-forming constituents. On the surface of the wire thereis disposed a coat 28 made up of three layers 29, 30 and 31 each ofwhich comprises one constituent selected from the group consisting ofalloying and slag-forming constituents. From 10 to 99 percent of themass of the constituents in the layers 25, 26 and 27 of the coat 24 andin the layers 29, 30 and 31 of the coat 28 is disposed on the surface ofthe cavity 23, whereas the total area of the layers 25, 26 and 27 of thecoat 24 and the layers 29, 30 and 31 of the coat 28 in cross section ofthe wire incorporating the identical constituents, equals from 0.001 to0.1 part of the area of the metal body 21. The ductility of theconstituent of the layer 27 adjacent to the metal body 21 and theconstituent of the layer 25 most distant therefrom is higher than theductility of the metal body 21. The ductility of the constituents of thelayer 31 adjacent to the metal body 21 and of the layer 29 most distanttherefrom, is higher than the ductility of the metal body 21.

An electrode wire shown in FIG. 4 comprises an alloyed metal body 32 anda charge 33 comprising at least one constituent from the groupconsisting of alloying and slag-forming constituents, and disposed infour cylindrical cavities 34. According to the invention disposed on thesurface of the cavities 34 is a coat 35 made up of three layers 36, 37and 38 each of which comprises one constituent selected from the groupconsisting of alloying and slag-forming constituents. On the surface ofthe wire there is disposed a coat 39 made up of three layers 40, 41 and42 each of which comprises one constituent selected from the groupconsisting of alloying and slag-forming constituents. From 10 to 99percent of the mass of the constituents in the layers 36, 37 and 38 ofthe coat 35 and in the layers 40, 41 and 42 of the coat 39 is disposedon the surface of the cavities 34, whereas the total area of the layers36, 37 and 38 of the coat 35 and the layers 40, 41 and 42 of the coat 39in cross section of the wire, incorporating the identical constituents,equals from 0.001 to 0.1 part of the area of the metal body 32.

The layers 40, 41 and 42 of the coat 39 comprise the alloying andslag-forming constituents conducting electrical current.

An electrode wire shown in FIG. 5 comprises an alloyed metal body 43 anda charge 44 comprising at least one constituent from the groupconsisting of alloying and slag-forming constituents and disposed inthree cylindrical cavities 45. According to the invention disposed onthe surfaces of the cavities 45 is a coat 46 made up of five layers 47,48, 49, 50 and 51 each of which comprises one constituent selected fromthe group consisting of alloying and slag-forming constituents. Disposedon the surface of the wire is a coat 52 made up of six layers 53, 54,55, 56, 57 and 53 each of which comprises one constituent selected fromthe group consisting of alloying and slag-forming constituents. From 10to 99 percent of the mass of the constituents in the layers 47, 48, 49,50 and 51 of the coat 46 and in the layers 53, 54, 55, 56, 57 and 58 ofthe coat 52 is disposed on the surfaces of the cavities 45, and thetotal area of the layers 47, 48, 49, 50 and 51 of the coat 46 and thelayers 53, 54, 55, 56, 57 and 58 of the coat 52 in cross section of thewire, incorporating the identical constituents, equals from 0.001 to 0.1part of the area of the metal body 43. The layers 47, 49 and 51 of thecoat 46 are made of the alloying constituents and the layers 48 and 50interposed therebetween are made of the slag-forming constituents.

An electrode wire illustrated in FIG. 6 comprises an alloyed metal body59 and a charge 60 comprising at least one constituent from the groupconsisting of alloying and slag-forming constituents and disposed in twocylindrical cavities 61. In accordance with the invention on thesurfaces of the cavities 61 there is disposed a coat 62 made up of threelayers 63, 64 and 65 each of which comprises one constituent selectedfrom the group consisting of alloying and slag-forming constituents.Disposed on the surface of the wire is a coat 66. A plane 67 is a planeof symmetry of the wire. The coat 66 has three layers 68, 69 and 70.Each of the layers 68 and 70 is made of one constituent selected fromthe group consisting of alloying and slag-forming constituents. Thelayer 69 includes sections 71 comprising alloying and slag-formingconstituents conducting electrical current and sections 72 alternatingwith the sections 71 along the wire and comprising alloying andslag-forming constituents posessing a current-insulating property, i.e.not conducting electrical current. From 10 to 99 percent of the mass ofthe constituents in the layers 63, 64 and 65 of the coat 62 and in thelayers 68, 69 and 70 of the coat 66 is disposed on the surfaces of thecavities 61, and the total area of the layers 63, 64 and 65 of the layer62 and the layers 68, 69 and 70 of the coat 66 in cross-section of thewire, incorporating the identical constituents, equals from 0.001 to 0.1part of the area of the metal body 59.

Further will be given specific examples of carrying out the invention.

EXAMPLE 1

An electrode wire of 1.2 mm diameter comprises a metal body comprisingin mass percent: C--0.08; Mn--0.8; Si--0.2; Fe--the balance, a chargedisposed in a cavity of the oval cross section and comprising powderedslag-forming constituents TiO₂, CaF₂, MgO and an alloying constituentMn, and coats disposed on the surfaces of the wire and the cavity andmade up each of two layers Cu and Ni which are alloying constituents. 90percent of the mass of the constituents Cu and Ni of the coat isdisposed on the surface of the wire, whereas 10 percent of their mass isdisposed on the surface of the cavity. The area of the layers of thecoats in cross section of the wire, incorporating the constituent Cu,amounts to 0.01 part of the area of the metal body and the area of thecoat layers incorporating the constituent Ni amounts to 0.005 part ofthe area of the metal body. The layers incorporating Cu are disposeddirectly on the metal body. The thickness of the layers made of Cuequals 2.4·10⁻³ mm and 4.5·10⁻³ mm respectively on the surfaces of thewire and the cavity, and the thickness of the layers made of Nirespectively on the surfaces of the wire and the cavity equals 1.2·10⁻³mm and 2.25·10⁻³ mm. The area of the cavity amounts to 10 percent of thearea of the wire in cross section. The ductility of the constituent Cuin the layer adjacent to the metal body and the ductility of theconstituent Ni in the layer most distant from the metal body are higherthan the ductility of the metal body. The ductility of the constituentsCu, Ni and the metal body is characterized by a reduction of area atfracture and is equal to 80, 72 and 43 percent, respectively.

EXAMPLE 2

An electrode wire of 1.2 mm diameter comprises a metal body comprisingin mass percent: C--0.08, Mn--0.9, Si--0.6, Fe--the balance, a chargedisposed in an oval cross-section cavity and comprising powderedslag-forming constituents CaO, BaF₂, MgF₂ and an alloying constituentNi, and coats disposed on the surfaces of the wire and the cavity andeach made up of two layers Cu and Al which are alloying constituents. 90percent of the mass of the constituents Cu and Al of the coat isdisposed on the surface of the wire and 10 percent of their mass isdisposed on the surface of the cavity. The total area of the layers ofthe coats in cross section of the wire comprising the constituent Cuamounts to 0.01 part of the area of the metal body, and comprising theconstituent Al amounts to 0.02 part of the area of the metal body. Thelayers made of Cu are disposed directly on the metal body. The thicknessof the layers made of Cu equal 2.4·10⁻³ mm and 18.0·10⁻³ mm on thesurface of the wire and on the surface of the cavity, respectively. Thethickness of the layers made of Al on the surface of the wire and on thesurface of the cavity equals 1.2·10⁻³ mm and 9.0·10⁻³ mm, respectively.

The area of the cavity amounts to 10 percent of the the area of the wirein cross section. The reduction of area at fracture of Cu, Al and themetal body is equal to 80, 86 and 36 percent, respectively.

EXAMPLE 3

An electrode wire of 1.2 mm diameter has a metal body comprising in masspercent: C--0.1, Mn--0.6, Si--0.4, Fe--the balance, a charge disposed ina cavity of the oval cross section and comprising powdered slag-formingconstituents V₂ O₅, NaF, MgO and alloying constituents Ti and Al, andcoats on the surfaces of the wire and the cavity, each made up of twolayers Cd and Cu which are alloying constituents. 50 percent of the massof the constituents of the coat is disposed on the wire surface and 50percent of the mass thereof is disposed on the cavity surface. The totalarea of the coat layers in the wire cross section, comprising theconstituent Cd amounts to 0.02 part of the area of the metal body andcomprising the constituent Cu amounts to 0.01 part of the area of themetal body. The layers comprising Cd are disposed directly on the metalbody. The thickness of the layers made of Cd equals 2.5·10⁻³ mm and45·10⁻³ mm on the surface of the wire and the cavity, respectively. Thethickness of the layers made of Cu on the surface of the wire and thecavity respectively euqals 1.25·10⁻³ mm and 22.5·10⁻³ mm. The cavityarea amounts to 10 percent of the wire area in cross section. Theductility of the constituent Cd in the layer adjacent to the metal bodyand the constituent Cu in the layer most distant therefrom is higherthan the ductility of the metal body. A reduction of area at fracture ofCd, Cu and the metal body is equal to 88, 80 and 49 percent,respectively.

EXAMPLE 4

An electrode wire of 1.2 mm diameter has a metal body comprising in masspercent: C--0.1, Mn--1.2, Ni--0.9, Mo--0.2, Si--0.15, Fe--the balance, acharge disposed in a cavity of the cylindrical shape and comprisingpowdered constituents CaF₂, BaF₂, SiO₂ and MnO and an alloyingconstituent Al, and a coat incorporating two layers of Ca and Zr on thesurface of the wire and four layers of constituents Ca, Zr, MgF₂ and Nion the surface of the cavity. 25 percent of the mass of the coatconstituents is disposed on the wire surface and 75 percent of the massthereof is disposed on the surface of the cavity. The total area of thecoat layers in cross section of the wire, comprising the constituentsCa, Zr, MgF₂ and Ni, respectively, amounts to 0.001 part of thecross-section area of the metal body. The thickness of the layers madeof Ca, Zr on the surface of the wire equals 0.13·10⁻³ mm. The thicknessof the layers consisting of Ca, Zr, MgF₂ and Ni on the surface of thecavity is equal to 2.25·10⁻³ mm, 2.25·10⁻³ mm, 4.5·10⁻³ mm and 4.5·10⁻³mm, respectively. The area of the cavity amounts to 10 percent of thewire cross-section area. The layers of Ca are disposed directly on themetal body. The ductility of Ca in the layers adjacent to the metal bodyand the ductility of Ni in the layer most distant from the metal bodyare higher than the ductility of the metal body. A reduction of area atfracture of Ca, Ni and the metal body equals 89, 72 and 30 percent,respectively. The ductility of MgF₂ is lower than the ductility of themetal body and the layer made of this constituent is interposed betweenthe layers made of Zr and Ni whose ductility is higher than theductility of the metal body. A reduction of area at fracture of Zr isequal to 65 percent.

EXAMPLE 5

An electrode wire with a diameter of 1.2 mm has a metal body comprisingin mass percent: C--0.1, Mn--0.9, Ni--0.4, M.--0.4, Si--0.3, Fe--thebalance, a charge disposed in a cavity of cylindrical shape andcomprising powdered constituents BaF₂, V₂ O₃ and CaO and an alloyingconstituent Cr, and a coat having two layers from constituents Co and Cuon the surface of the wire and four layers from constituents Nb, Al,BaCl₂ and Ni on the surface of the cavity. The layer from theconstituent Co and the layer from the constituent Nb are disposeddirectly on the metal body. 90 percent of the mass of the coatconstituents is disposed on the surface of the cavity and 10 percent ofthe mass is disposed on the surface of the wire. The total area of thecoat layers in the wire cross section, made of the constituents Co, Cu,Nb, Al, BaCl₂ and Ni respectively amounts to 0.0013, 0.0013, 0.002,0.002, 0.004 and 0.004 part of the cross-section area of the metal body.The thickness of the layers consisting of Co and Cu on the wire surfaceequals 0.35·10⁻³ mm and 0.35·10⁻³ mm, respectively. The thickness of thelayers consisting of Nb, Al, BaCl₂ and Ni equals 9.0·10⁻³ mm, 9.0·10⁻³mm, 18.0·10⁻³ mm, respectively. The area of the cavity amounts to 10percent of the wire cross-section area. The ductility of Co in the layeradjacent to the metal body and the ductility of Ni in the layer mostdistant from the metal body are higher than the ductility of the metalbody. A reduction of area at fracture of Co, Ni and the metal bodyequals 76, 72 and 36 percent, respectively. A percentage reduction ofarea of BaCl₂ amounts to 16 percent. The ductility of the slag-formingconstituent BaCl₂ is lower than the ductility of the metal body, and thelayer of BaCl₂ is interposed between the layers Al and Ni, the ductilityof which is higher than the ductility of the metal body.

EXAMPLE 6

An electrode wire with a diameter of 1.2 mm has a metal body comprisingin mass percent: C--0.1, Mn--0.9, Ni--0.2, Mo--0.2, Si--0.15, Fe--thebalance, a charge disposed in a cavity of the cylindrical shape andcomprising powdered constituents TiO₂, V₂ O₅, and CaO, and alloyingconstituents Cr and Co, and a coat having two layers from constituentsCu and Ni on the surface of the wire and four layers from Cu, Al, MgF₂and Ni on the surface of the cavity. The layers from the constituent Cuare disposed directly on the metal body. 99 percent of the mass of theconstituents of the coat is disposed on the surface of the cavity and 1percent of the mass of the coat is disposed on the surface of the wire.

The total area of the coat layers in the wire cross section, consistingof the constituents Cu, Al, MgF₂ and Ni, amounts to 0.002, 0.004, 0.004and 0.002 part of the cross-section area of the metal body,respectively. The thickness of the layers consisting of Cu and Ni on thesurface of the wire equals 0.15·10⁻³ mm for each constituent. Thethickness of the layers made of Cu, Al, MgF₂ and Ni is equal to 9.0·10⁻³mm, 18.0·10⁻³ mm, 9.0·10⁻³ mm, respectively. The area of the cavityamounts to 10 percent of the wire cross-section area.

EXAMPLE 7

An electrode wire of 1.4 mm diameter has a metal body comprising in masspercent: C--0.12, Mn--1.4, Si--0.4, Mo--0.2, Ti--0.2, Fe--the balance, acharge disposed in a longitudinal cavity and comprising a slag-formingconstituent TiO₂, and a coat made up of three layers consisting ofconstituents Cd, W and Al. 90 percent of the mass of the coat isdisposed on the surface of the wire and the remaining 10 percent, on thesurface of the cavity. The total area of the coat layers in crosssection of the wire, consisting of the constituents Cd, W and Al, equals0.08, 0.01, 0.08 part of the metal body cross-section area,respectively. The thickness of the layers made of Cd, W and Al on thesurface of the wire is equal to 20.5·10⁻³ mm, 2.0·10⁻³ mm, 20.5·10⁻³ mm,respectively. The thickness of the layers from Cd, W and Al on thesurface of the cavity equals 50.0·10⁻ 3 mm, 6.2·10⁻³ mm, 50.0·10⁻³ mm,respectively. The area of the cavity amounts to 20 percent of the wirearea in cross section. The coat layers from W whose ductility(percentage reduction of area is 8 percent) is lower than the ductilityof the metal body (elongation is 40 percent) are interposed between thelayers from Cd and Al whose ductility is higher than that of the metalbody (percentage reduction of area of Cd and Al equals 88 and 86percent, respectively). Instead of TiO₂ the charge may incorporate asslag-forming constituents the constituents selected from the groupconsisting of chlorides, fluorides, carbides and oxides of Mg, Al, Si,Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Cd, Ba, La, Ta, W, Ce.

EXAMPLE 8

An electrode wire of 1.4 mm diameter comprises a metal body comprisingin mass percent: C--0.12, Mn--1.4, Si--0.4, Mo--0.2, Ti--0.2, Fe--thebalance, a charge disposed in a longitudinal cavity and comprisingslag-forming constituents TiO₂, NaCl and Cr, and a coat made up of threelayers consisting of constituents Cd, W, Al. 90 percent of the mass ofthe coat is disposed on the surface of the wire and the remaining 10percent, on the surface of the cavity. The total area of the coat layersin the wire cross section, consisting of Cd, W and Al, is equal to 0.08,0.01, 0.08 part of the metal body cross-section area, respectively. Thethickness of the layers from Cd, W and Al on the surface of the wireequals 20.5·10⁻³ mm, 2.6·10⁻³ mm, 20.5·10⁻³ mm, respectively. Thethickness of the layers from Cd, W and Al on the surface of the cavityequals 50·10⁻³ mm, 6.2·10⁻³ mm, 50·10⁻³ mm, respectively. The area ofthe cavity amounts to 20 percent of the wire area in cross section. Usedinstead of the alloying constituent Cd, W, Al, Cr may be Mg, Si, Ca, Ti,V, Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Ba, La, Ta, Ce.

EXAMPLE 9

An electrode wire of 1.4 mm diameter comprises a metal body comprisingin mass percent: C--0.07, Mn--1.4, Al--1.2, Fe--the balance, a chargedisposed in four cylindrical cavities and comprising slag-formingconstituents CaF₂, V₂ O₅ and alloying constituents Cr and Nb, and a coatmade up of three layers consisting of constituents Co, BaF₂ and Ta. 90percent of the mass of the coat is disposed on the surface of the wireand the remaining 10 percent, on the surface of the cavities. Thethickness of the layers from Co, BaF₂ and Ta on the surface of the wireequals 20.5·10⁻³ mm, 2.6·10⁻³ mm and 20.5·10⁻³ mm, respectively, and onthe surface of each cavity equals 12·10⁻³ mm, 1.4·10⁻³ mm, respectively.The area of each cavity amounts to 5 percent of the area of the wire incross section. The layer most distant from the metal body is made fromthe alloying constituent Ta and the layer adjacent thereto is made fromthe alloying constituent Co. The layer interposed therebetween is madefrom the slag-forming constituent BaF₂.

EXAMPLE 10

An electrode wire is similar to the wire of Example 9, except for theslag-forming constituent BaF₂, instead of which a slag-formingconstituent CaF₂ is used.

EXAMPLE 11

An electrode wire with a diameter of 1.0 mm comprises a metal bodycomprising in mass percent: C--0.12, Mn--0.7, Si--0.03, Fe--the balance,a charge disposed in three longitudinal cavities and comprising CaF₂,BaCl₂ and V, and a coat made up of five layers consisting ofconstituents Zr, MnC, Cd, WC, Al.

The thickness of the coat layers on the wire surface made of Zr, MnC,Cd, WC, Al is equal to 5.0·10⁻³ mm, 2.0·10⁻³ mm, 5.0·10⁻³ mm, 2.0·10⁻³mm, 5.0·10⁻³ mm, respectively. The thickness of the coat layers from Zr,MnC, Cd, WC, Al on the surface of each cavity equals 10.0·10⁻³ mm,6.0·10⁻³ mm, 10.0·10⁻³ mm, 6.0·10⁻³ mm, 10.0·10⁻³ mm, respectively. Thecoat layers from the constituents MnO and WC whose hardness is higherthan the hardness of the metal body are interposed between the layersfrom the constituents Zr, Cd, Al whose hardness is lower than thehardness of the metal body. The hardness of Zr, MnO, Cd, WC, Al and ofthe metal body is equal to 3, 6, 2.2, 9.7, 2.8, 5, respectively.

EXAMPLE 12

An electrode wire similar to the wire of Example 8s is characterized inthat the charge additionally comprises a slag-forming constituent BaF₂.The hardness of the constituents Cd in the layers adjacent to the metalbody and Al in the layer most distant from the metal body is lower thanthe hardness of the metal body. The hardness of Cd, Al and the metalbody is equal to 2.2, 2.8 and 6, respectively.

EXAMPLE 13

An electrode wire similar to the wire of Example 9 is characterized inthat the charge additionally comprises a slag-forming constituent Cr₂ O₃and does not comprise the alloying constituent Cr. On the surface of thewire there is disposed a coat whose layers are made from alloyingconstituents Co and Ta, as well as from the slag-forming constituentBaF₂ conducting electrical current.

EXAMPLE 14

An electrode wire similar to the wire of Example 9 is characterized inthat in the coat instead of the layer from the slag-forming constituentBaF₂ use is made of a layer consisting of alternate sections fromconstituents Cu and NaCl. The alloying constituent Cu conductselectrical current, whereas the slag-forming constituent NaCl does notconduct electrical current.

The electrode wire described in Examples 1 through 14 makes it possibleto reduce losses of the alloying constituents in the process of meltingthe wire by from 4 to 10 times, to increase the efficiency of thewelding process by from 3 to 7 times, to prevent metal spatter. The useof the foregoing coats increases the metal body ductility during coldworking by from 2 to 3 times and provides for obtaining a wire with adiameter less than 1.6 mm. The use of the wire having a diameter lessthan 1.6 mm makes it possible to obtain welds featuring a higher impactstrength and a lower porosity.

INDUSTRIAL APPLICABILITY

The invention may advantageously be used in consumable-electrode arcwelding both in shielding gases and without additional shielding whenmanufacturing metallic structures from low-carbon and low-alloyedsteels.

In addition, the electrode wire of the invention may be used insurfacing and also as a filler material in welding with a nonconsumable(tungsten) electrode or in brazing.

We claim:
 1. An electrode wire comprising an alloyed metal body (1; 10;21; 32; 43; 59) provided with at least one longitudinal cavity (3; 12;23; 34; 45; 61) filled with a charge (2; 11; 22; 33; 44; 60) comprisingat least one constituent selected from the group consisting ofslag-forming and alloying constituents, characterized in that on thesurface of the cavity (3; 12; 23; 34; 45; 61) and the wire there isdisposed a coat (4 and 7; 13 and 18; 24 and 28; 35 and 39; 46 and 52; 62and 66) made up of at least two layers (5, 6; 8, 9; 14, 15, 16, 17; 19,20; 25, 26, 27; 29, 30, 31; 36, 37, 38; 40, 41, 42; 47, 48, 49, 50, 51;53, 54, 55, 56, 57, 58; 63, 64, 65; 68, 69, 70) each of which consistson one constituent selected from the group consisting of alloying andslag-forming constituents, from 10 to 99 percent of the mass of theconstituents in the layers (5, 6; 8, 9; 14, 15, 16, 17; 19, 20; 25, 26,27; 29, 30, 31; 36, 37, 38; 40, 41, 42; 47, 48, 49, 50, 51; 53, 54, 55,56, 57, 58; 63, 64, 65; 68, 69, 70) of the coat (4, 7; 13, 18; 24, 28;35, 39; 46, 52; 62, 66) being disposed on the surface of the cavity (3;12; 23; 34; 45; 61), and the total area of the layers (5, 6; 8, 9; 14,15, 16, 17; 19, 20; 25, 26, 27; 29, 30, 31; 36, 37, 38; 40, 41, 42; 47,48, 49, 50, 51; 53, 54, 55, 56, 57, 58; 63, 64, 65; 68, 69, 70) of thecoat (4, 7; 13, 18; 24, 28; 35, 39; 46, 52; 62, 66) in cross section ofthe wire, consisting of the identical constituents, being equal to from0.001 to 0.1 part of the area of the metal body (1; 10; 21; 32; 43; 59).2. An electrode wire according to claim 1, characterized in that thealloying constituents are selected from the group consisting of Mg, Al,Si, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Cd, Ba, La, Ta, W, Ceand the slag-forming constituents are selected from the group consistingof carbides oxides, chlorides and fluorides of Mg, Al, Si, Ca, Ti, V,Cr, Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Cd, Ba, La, Ta, W, Ce.
 3. Anelectrode wire according to claim 1, characterized in that the ductilityof the constituents of the layer (27, 31) adjacent to the metal body(21) and the ductility of the constituents of the layer (25, 29) mostdistant therefrom are higher than the ductility of the metal body (21).4. An electrode wire according to claim 3, characterized in that thelayers (26, 30) of the coat (24, 28) made from the constituents theductility of which is lower than the ductility of the metal body (21)are interposed between the layers (25 and 27, 29 and 31) made from theconstituents the ductility of which is higher than the ductility of themetal body (21).
 5. An electrode wire according to claim 1,characterized in that on the surface of the wire there is disposed thecoat (39) the layers (40, 41, 42) of which contain alloying andslag-forming constituents conducting electrical current.
 6. An electrodewire according to claim 1, characterized in that on the surface of thewire there is disposed the coat (66) made up of at least three layers(68, 69, 70) in which the layer (70) most distant from the metal body(59) and the layer (68) adjacent thereto are made from alloying andslag-forming constituents conducting electrical current, and the layer(69) interposed between the layers (68, 70) is made up of sections (71)incorporating alloying and slag-forming constituents conductingelectrical current and of sections (72) alternated with the sections(71) and incorporating alloying and slag-forming constituents posessinga current-insulating property.
 7. An electrode wire according to claim 1characterized in that on the surface of the wire there is disposed thecoat (28) made up of at least three layers in which the layer (31) mostdistant from the metal body (21) and the layer (29) adjacent theretoincorporates alloying constituents, and the layer (30) interposedbetween the layers (29 and 31) incorporates slag-forming constituents.8. An electrode wire according to claim 1 characterized in that thehardness of the constituents of the layer (29) adjacent to the metalbody (21) and the layer (31) most distant therefrom is lower than thehardness of the metal body (21).
 9. An electrode wire according to claim1 characterized in that the layers (30) of the coat (28) made from theconstituents the hardness of which is higher than the hardness of themetal body (21) are interposed between the layers 29 and 31) made fromthe constituents the hardness of which is lower than the hardness of themetal body (21).